The present invention relates to injection apparatus or equipment for the supply of material such as gaseous and/or particulate material in the form of powder, granules, chips or similar shapes to a liquid, for example metal melt. The apparatus includes a rotation body which is designed to be lowered down into the liquid and which is mounted on and driven by a shaft of a drive unit.
Previous equipment and methods are known for processing and adding particulate material to a liquid as stated above. Thus, Norwegian Patent No. 155,447 discloses a rotor for processing and adding material to a liquid, whereby the rotor comprises a rotationally symmetrical hollow body and whereby the material is added to the liquid via a bore in the rotor shaft and onwards out through a hole in the side of the hollow body together with the liquid which, on account of centripetal force, is sucked in through an opening in the base and circulated through the body. Even if this rotor in itself causes the material to be well mixed in the melt, over time the material will build up inside the rotor, especially where large particles are involved, and eventually block it completely.
Furthermore, EP-A-0065854 describes a procedure for removing alkaline and earth-alkaline metals from aluminum melts whereby aluminum fluoride is introduced in powder form into an eddy produced in the melt. Processing takes place in a cylindrical container with the ability to hold 3-5 tonnes of aluminum melt. This known method requires substantial agitation of the melt to obtain the desired effect. However, such powerful agitation is not desirable as it causes air to be pumped into the melt. Furthermore, the quantity of aluminum fluoride which is required to process each tonne of melt is relatively high. Other generally known methods (for example as disclosed in Norwegian patent application No. 881,370) involve adding powder to a melt by means of a carrier gas through one or more lances. The disadvantages of using lances are that the consumption of gas is high and the efficiency is low. Even if the efficiency can be increased somewhat by also using an agitation device, the consumption of gas is equally high and the particles continue to be insufficiently mixed into the melt.